We present a review of the concept's history and discuss different pos
sible varieties of ''folie a deux''. Following this we report the case
of a couple whose ''folie a deux'' has lasted for ten years. They hav
e four of their own children and three further children from the husba
nd's first marriage. Of special interest is the personality of the pro
tagonists, their psychological assessment, and the so far ineffective
therapeutic interventions that have been undertaken in efforts to save
the children.